3 # -*- coding: utf-8 -*-
5 # Copyright (C) 2013 GRNET S.A.
7 # This program is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 2 of the License, or
10 # (at your option) any later version.
12 # This program is distributed in the hope that it will be useful, but
13 # WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 # General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with this program; if not, write to the Free Software
19 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 """This module provides the code for handling BSD disklabels"""
31 from collections import namedtuple
32 from collections import OrderedDict
39 BBSIZE = 8192 # size of boot area with label
40 SBSIZE = 8192 # max size of fs superblock
42 DISKMAGIC = 0x82564557
46 """Represents a Master Boot Record."""
47 class Partition(object):
48 """Represents a partition entry in MBR"""
51 def __init__(self, raw_part):
52 """Create a Partition instance"""
59 ) = struct.unpack(self.fmt, raw_part)
62 """Pack the partition values into a binary string"""
63 return struct.pack(self.fmt,
73 """Returns the size of an MBR partition entry"""
74 return struct.calcsize(MBR.Partition.fmt)
77 return "%02Xh %s %02Xh %s %d %d" % (self.status,
78 self.unpack_chs(self.start),
80 self.unpack_chs(self.end),
86 """Unpacks a CHS address string to a tuple."""
90 head = struct.unpack('<B', chs[0])[0]
91 sector = struct.unpack('<B', chs[1])[0] & 0x3f
92 cylinder = (struct.unpack('<B', chs[1])[0] & 0xC0) << 2 | \
93 struct.unpack('<B', chs[2])[0]
95 return (cylinder, head, sector)
98 def pack_chs(cylinder, head, sector):
99 """Packs a CHS tuple to an address string."""
101 assert 1 <= sector <= 63
102 assert 0 <= head <= 255
105 # If the cylinders overflow then put the value (1023, 254, 63) to
106 # the tuple. At least this is what OpenBSD does.
113 byte1 = (cylinder >> 2) & 0xC0 | sector
114 byte2 = cylinder & 0xff
116 return struct.pack('<BBB', byte0, byte1, byte2)
118 def __init__(self, block):
119 """Create an MBR instance"""
121 self.fmt = "<444s2x16s16s16s16s2s"
122 raw_part = {} # Offset Length Contents
123 (self.code_area, # 0 440(max. 446) code area
124 # 440 2(optional) disk signature
125 # 444 2 Usually nulls
126 raw_part[0], # 446 16 Partition 0
127 raw_part[1], # 462 16 Partition 1
128 raw_part[2], # 478 16 Partition 2
129 raw_part[3], # 494 16 Partition 3
130 self.signature # 510 2 MBR signature
131 ) = struct.unpack(self.fmt, block)
135 self.part[i] = self.Partition(raw_part[i])
138 """Return the size of a Master Boot Record."""
139 return struct.calcsize(self.fmt)
142 """Pack an MBR to a binary string."""
143 return struct.pack(self.fmt,
155 ret += "Partition %d: %s\n" % (i, self.part[i])
156 ret += "Signature: %s %s\n" % (hex(ord(self.signature[0])),
157 hex(ord(self.signature[1])))
158 title = "Master Boot Record"
159 return "%s\n%s\n%s\n" % (title, len(title) * "=", ret)
163 """Represents a BSD Disk"""
165 def __init__(self, device):
166 """Create a Disk instance"""
169 self.disklabel = None
171 with open(device, "rb") as d:
172 sector0 = d.read(BLOCKSIZE)
173 self.mbr = MBR(sector0)
176 ptype = self.mbr.part[i].type
177 if ptype in (0xa5, 0xa6, 0xa9):
178 d.seek(BLOCKSIZE * self.mbr.part[i].first_sector)
180 if ptype == 0xa5: # FreeBSD
181 self.disklabel = BSDDisklabel(d)
182 elif ptype == 0xa6: # OpenBSD
183 self.disklabel = OpenBSDDisklabel(d)
185 self.disklabel = BSDDisklabel(d)
188 assert self.disklabel is not None, "No *BSD partition found"
191 """Write the changes back to the media"""
192 with open(self.device, 'rw+b') as d:
193 d.write(self.mbr.pack())
195 d.seek(self.mbr.part[self.part_num].first_sector * BLOCKSIZE)
196 self.disklabel.write_to(d)
199 """Print the partitioning info of the Disk"""
200 return str(self.mbr) + str(self.disklabel)
202 def enlarge(self, new_size):
203 """Enlarge the disk and return the last usable sector"""
206 end = self.disklabel.enlarge(new_size)
209 start = self.mbr.part[self.part_num].first_sector
210 self.mbr.part[self.part_num].sector_count = end - start + 1
212 ntracks = self.disklabel.field['ntracks']
213 nsectors = self.disklabel.field['nsectors']
215 cylinder = end // (ntracks * nsectors)
216 header = (end // nsectors) % ntracks
217 sector = (end % nsectors) + 1
218 chs = MBR.Partition.pack_chs(cylinder, header, sector)
219 self.mbr.part[self.part_num].end = chs
221 def enlarge_last_partition(self):
222 """Enlarge the last partition to cover up all the free space"""
223 self.disklabel.enlarge_last_partition()
225 def get_last_partition_id(self):
226 """Get the ID of the last partition"""
227 return self.disklabel.get_last_partition_id()
230 """Get the Disklabel Unique Identifier (works only for OpenBSD)"""
231 if 'uid' in self.disklabel.field:
232 return self.disklabel.field['uid']
237 class DisklabelBase(object):
238 """Disklabel base class"""
239 __metaclass__ = abc.ABCMeta
241 def __init__(self, device):
242 """Create a Disklabel instance"""
244 # Subclasses need to overwrite this
248 @abc.abstractproperty
250 """Fields format string for the disklabel fields"""
253 def pack(self, checksum=None):
254 """Return a binary copy of the Disklabel block"""
257 for k, v in self.field.iteritems():
260 if checksum is not None:
261 out['checksum'] = checksum
263 return struct.pack(self.fmt, * out.values() + [self.ptable.pack()])
265 def compute_checksum(self):
266 """Compute the checksum of the disklabel"""
268 raw = cStringIO.StringIO(self.pack(0))
273 checksum ^= struct.unpack('<H', uint16)[0]
281 def enlarge(self, new_size):
282 """Enlarge the disk and return the last usable sector"""
285 def write_to(self, device):
286 """Write the disklabel to a device"""
288 # The disklabel starts at sector 1
289 device.seek(BLOCKSIZE, os.SEEK_CUR)
290 device.write(self.pack())
293 def enlarge_last_partition(self):
294 """Enlarge the last partition to consume all the usable space"""
298 def get_last_partition_id(self):
299 """Get the ID of the last partition"""
304 """Print the Disklabel"""
308 class PartitionTableBase(object):
309 """Base Class for disklabel partition tables"""
310 __metaclass__ = abc.ABCMeta
312 @abc.abstractproperty
314 """Partition fields format string"""
317 @abc.abstractproperty
319 """The partition fields"""
322 def __init__(self, ptable, pnumber):
323 """Create a Partition Table instance"""
325 self.Partition = namedtuple('Partition', self.fields)
328 size = struct.calcsize(self.fmt)
329 raw = cStringIO.StringIO(ptable)
331 for _ in xrange(pnumber):
333 self.Partition(*struct.unpack(self.fmt, raw.read(size)))
339 """Print the Partition table"""
341 for i in xrange(len(self.part)):
342 val += "%c: %s\n" % (chr(ord('a') + i), str(self.part[i]))
346 """Packs the partition table into a binary string."""
348 for i in xrange(len(self.part)):
349 ret += struct.pack(self.fmt, *self.part[i])
350 return ret + ((364 - len(self.part) * 16) * '\x00')
353 class BSDDisklabel(DisklabelBase):
354 """Represents an BSD Disklabel"""
356 class PartitionTable(PartitionTableBase):
357 """Represents a BSD Partition Table"""
361 """Partition fields format string"""
366 """The partition fields"""
367 return [ # Offset Length Contents
368 'size', # 0 4 Number of sectors in partition
369 'offset', # 4 4 Starting sector of the partition
370 'fsize', # 8 4 File system basic fragment size
371 'fstype', # 12 1 File system type
372 'frag', # 13 1 File system fragments per block
373 'cpg' # 14 2 File system cylinders per group
378 return "<IHH16s16sIIIIIIHHIHHHHIII20s20sIHHII364s"
380 def __init__(self, device):
381 """Create a BSD DiskLabel instance"""
382 super(BSDDisklabel, self).__init__(device)
384 # Disklabel starts at offset one
385 device.seek(BLOCKSIZE, os.SEEK_CUR)
386 sector1 = device.read(BLOCKSIZE)
388 d_ = OrderedDict() # Off Len Content
389 (d_["magic"], # 0 4 Magic
390 d_["dtype"], # 4 2 Drive Type
391 d_["subtype"], # 6 2 Subtype
392 d_["typename"], # 8 16 Type Name
393 d_["packname"], # 24 16 Pack Identifier
394 d_["secsize"], # 32 4 Bytes per sector
395 d_["nsectors"], # 36 4 Data sectors per track
396 d_["ntracks"], # 40 4 Tracks per cylinder
397 d_["ncylinders"], # 44 4 Data cylinders per unit
398 d_["secpercyl"], # 48 4 Data sectors per cylinder
399 d_["secperunit"], # 52 4 Data sectors per unit
400 d_["sparespertrack"], # 56 2 Spare sectors per track
401 d_["sparespercyl"], # 58 2 Spare sectors per cylinder
402 d_["acylinders"], # 60 4 Alternative cylinders per unit
403 d_["rpm"], # 64 2 Rotation Speed
404 d_["interleave"], # 66 2 Hardware sector interleave
405 d_["trackskew"], # 68 2 Sector 0 skew, per track
406 d_["cylskew"], # 70 2 Sector 0 skew, per cylinder
407 d_["headswitch"], # 72 4 Head switch time
408 d_["trkseek"], # 76 4 Track-to-track seek
409 d_["flags"], # 80 4 Generic Flags
410 d_["drivedata"], # 84 5*4 Drive-type specific information
411 d_["spare"], # 104 5*4 Reserved for future use
412 d_["magic2"], # 124 4 Magic Number
413 d_["checksum"], # 128 2 Xor of data including partitions
414 d_["npartitions"], # 130 2 Number of partitions following
415 d_["bbsize"], # 132 4 size of boot area at sn0, bytes
416 d_["sbsize"], # 136 4 Max size of fs superblock, bytes
417 ptable_raw # 140 16*16 Partition Table
418 ) = struct.unpack(self.fmt, sector1)
420 assert d_['magic'] == d_['magic2'] == DISKMAGIC, "Disklabel not valid"
421 self.ptable = self.PartitionTable(ptable_raw, d_['npartitions'])
424 def enlarge(self, new_size):
425 raise NotImplementedError
427 def enlarge_last_partition(self):
428 raise NotImplementedError
430 def get_last_partition_id(self):
431 raise NotImplementedError
434 """Print the Disklabel"""
438 # Those fields may contain null bytes
439 typename = self.field['typename'].strip('\x00').strip()
440 packname = self.field['packname'].strip('\x00').strip()
443 "%s\n%s\n" % (title, len(title) * "=") + \
444 "Magic Number: 0x%(magic)x\n" \
445 "Drive type: %(dtype)d\n" \
446 "Subtype: %(subtype)d\n" % self.field + \
447 "Typename: %s\n" % typename + \
448 "Pack Identifier: %s\n" % packname + \
449 "# of bytes per sector: %(secsize)d\n" \
450 "# of data sectors per track: %(nsectors)d\n" \
451 "# of tracks per cylinder: %(ntracks)d\n" \
452 "# of data cylinders per unit: %(ncylinders)d\n" \
453 "# of data sectors per cylinder: %(secpercyl)d\n" \
454 "# of data sectors per unit: %(secperunit)d\n" \
455 "# of spare sectors per track: %(sparespertrack)d\n" \
456 "# of spare sectors per cylinder: %(sparespercyl)d\n" \
457 "Alt. cylinders per unit: %(acylinders)d\n" \
458 "Rotational speed: %(rpm)d\n" \
459 "Hardware sector interleave: %(interleave)d\n" \
460 "Sector 0 skew, per track: %(trackskew)d\n" \
461 "Sector 0 skew, per cylinder: %(cylskew)d\n" \
462 "Head switch time, usec: %(headswitch)d\n" \
463 "Track-to-track seek, usec: %(trkseek)d\n" \
464 "Generic Flags: %(flags)r\n" \
465 "Drive data: %(drivedata)r\n" \
466 "Reserved for future use: %(spare)r\n" \
467 "The magic number again: 0x%(magic2)x\n" \
468 "Checksum: %(checksum)d\n" \
469 "Number of partitions: %(npartitions)d\n" \
470 "Size of boot aread at sn0: %(bbsize)d\n" \
471 "Max size of fs superblock: %(sbsize)d\n" % self.field + \
475 class OpenBSDDisklabel(DisklabelBase):
476 """Represents an OpenBSD Disklabel"""
478 class PartitionTable(PartitionTableBase):
479 """Reprepsents an OpenBSD Partition Table"""
487 return [ # Offset Length Contents
488 'size', # 0 4 Number of sectors in the partition
489 'offset', # 4 4 Starting sector of the partition
490 'offseth', # 8 2 Starting sector (high part)
491 'sizeh', # 10 2 Number of sectors (high part)
492 'fstype', # 12 1 Filesystem type
493 'frag', # 13 1 Filesystem Fragments per block
494 'cpg' # 14 2 FS cylinders per group
497 def setpsize(self, i, size):
498 """Set size for partition i"""
500 self.part[i] = self.Partition(
501 size & 0xffffffff, tmp.offset, tmp.offseth, size >> 32,
502 tmp.fstype, tmp.frag, tmp.cpg)
504 def getpsize(self, i):
505 """Get size for partition i"""
506 return (self.part[i].sizeh << 32) + self.part[i].size
508 def setpoffset(self, i, offset):
509 """Set offset for partition i"""
511 self.part[i] = self.Partition(
512 tmp.size, offset & 0xffffffff, offset >> 32, tmp.sizeh,
515 def getpoffset(self, i):
516 """Get offset for partition i"""
517 return (self.part[i].offseth << 32) + self.part[i].offset
521 return "<IHH16s16sIIIIII8sIHHIII20sHH16sIHHII364s"
523 def __init__(self, device):
524 """Create a DiskLabel instance"""
526 super(OpenBSDDisklabel, self).__init__(device)
528 # Disklabel starts at offset one
529 device.seek(BLOCKSIZE, os.SEEK_CUR)
530 sector1 = device.read(BLOCKSIZE)
532 d_ = OrderedDict() # Off Len Content
533 (d_["magic"], # 0 4 Magic
534 d_["dtype"], # 4 2 Drive Type
535 d_["subtype"], # 6 2 Subtype
536 d_["typename"], # 8 16 Type Name
537 d_["packname"], # 24 16 Pack Identifier
538 d_["secsize"], # 32 4 Bytes per sector
539 d_["nsectors"], # 36 4 Data sectors per track
540 d_["ntracks"], # 40 4 Tracks per cylinder
541 d_["ncylinders"], # 44 4 Data cylinders per unit
542 d_["secpercyl"], # 48 4 Data sectors per cylinder
543 d_["secperunit"], # 52 4 Data sectors per unit
544 d_["uid"], # 56 8 Unique label identifier
545 d_["acylinders"], # 64 4 Alt cylinders per unit
546 d_["bstarth"], # 68 2 Start of useable region (high part)
547 d_["bendh"], # 70 2 Size of usable region (high part)
548 d_["bstart"], # 72 4 Start of useable region
549 d_["bend"], # 76 4 End of usable region
550 d_["flags"], # 80 4 Generic Flags
551 d_["drivedata"], # 84 5*4 Drive-type specific information
552 d_["secperunith"], # 104 2 Number of data sectors (high part)
553 d_["version"], # 106 2 Version
554 d_["spare"], # 108 4*4 Reserved for future use
555 d_["magic2"], # 124 4 Magic number
556 d_["checksum"], # 128 2 Xor of data including partitions
557 d_["npartitions"], # 130 2 Number of partitions in following
558 d_["bbsize"], # 132 4 size of boot area at sn0, bytes
559 d_["sbsize"], # 136 4 Max size of fs superblock, bytes
560 ptable_raw # 140 16*16 Partition Table
561 ) = struct.unpack(self.fmt, sector1)
563 assert d_['magic'] == d_['magic2'] == DISKMAGIC, "Disklabel not valid"
564 self.ptable = self.PartitionTable(ptable_raw, d_['npartitions'])
567 def setdsize(self, dsize):
569 self.field['secperunith'] = dsize >> 32
570 self.field['secperunit'] = dsize & 0xffffffff
574 return (self.field['secperunith'] << 32) + self.field['secperunit']
576 dsize = property(getdsize, setdsize, None, "disk size")
578 def setbstart(self, bstart):
579 """Set start of useable region"""
580 self.field['bstarth'] = bstart >> 32
581 self.field['bstart'] = bstart & 0xffffffff
584 """Get start of usable region"""
585 return (self.field['bstarth'] << 32) + self.field['bstart']
587 bstart = property(getbstart, setbstart, None, "start of usable region")
589 def setbend(self, bend):
590 """Set end of useable region"""
591 self.field['bendh'] = bend >> 32
592 self.field['bend'] = bend & 0xffffffff
595 """Get end of usable region"""
596 return (self.field['bendh'] << 32) + self.field['bend']
598 bend = property(getbend, setbend, None, "end of usable region")
600 def enlarge(self, new_size):
601 """Enlarge the disk and return the last usable sector"""
603 assert new_size >= self.dsize, \
604 "New size cannot be smaller that %s" % self.dsize
607 self.dsize = new_size
608 self.field['ncylinders'] = self.dsize // (self.field['nsectors'] *
609 self.field['ntracks'])
610 self.bend = (self.field['ncylinders'] * self.field['nsectors'] *
611 self.field['ntracks'])
613 # Partition 'c' descriptes the entire disk
614 self.ptable.setpsize(2, new_size)
616 # Update the checksum
617 self.field['checksum'] = self.compute_checksum()
619 # The last usable sector is the end of the usable region minus one
622 def get_last_partition_id(self):
623 """Returns the id of the last partition"""
626 # Don't check partition 'c' which is the whole disk
627 for i in filter(lambda x: x != 2, range(len(self.ptable.part))):
628 curr_end = self.ptable.getpsize(i) + self.ptable.getpoffset(i)
633 assert end > 0, "No partition found"
637 def enlarge_last_partition(self):
638 """Enlarge the last partition to cover up all the free space"""
640 part_num = self.get_last_partition_id()
642 end = self.ptable.getpsize(part_num) + self.ptable.getpoffset(part_num)
644 assert end > 0, "No partition found"
646 if self.ptable.part[part_num].fstype == 1: # Swap partition.
647 #TODO: Maybe create a warning?
650 if end > (self.bend - 1024):
653 self.ptable.setpsize(
654 part_num, self.bend - self.ptable.getpoffset(part_num) - 1024)
656 self.field['checksum'] = self.compute_checksum()
659 """Print the Disklabel"""
661 # Those values may contain null bytes
662 typename = self.field['typename'].strip('\x00').strip()
663 packname = self.field['packname'].strip('\x00').strip()
665 duid = "".join(x.encode('hex') for x in self.field['uid'])
669 "%s\n%s\n" % (title, len(title) * "=") + \
670 "Magic Number: 0x%(magic)x\n" \
671 "Drive type: %(dtype)d\n" \
672 "Subtype: %(subtype)d\n" % self.field + \
673 "Typename: %s\n" % typename + \
674 "Pack Identifier: %s\n" % packname + \
675 "# of bytes per sector: %(secsize)d\n" \
676 "# of data sectors per track: %(nsectors)d\n" \
677 "# of tracks per cylinder: %(ntracks)d\n" \
678 "# of data cylinders per unit: %(ncylinders)d\n" \
679 "# of data sectors per cylinder: %(secpercyl)d\n" \
680 "# of data sectors per unit: %(secperunit)d\n" % self.field + \
681 "DUID: %s\n" % duid + \
682 "Alt. cylinders per unit: %(acylinders)d\n" \
683 "Start of useable region (high part): %(bstarth)d\n" \
684 "Size of useable region (high part): %(bendh)d\n" \
685 "Start of useable region: %(bstart)d\n" \
686 "End of usable region: %(bend)d\n" \
687 "Generic Flags: %(flags)r\n" \
688 "Drive data: %(drivedata)r\n" \
689 "Number of data sectors (high part): %(secperunith)d\n" \
690 "Version: %(version)d\n" \
691 "Reserved for future use: %(spare)r\n" \
692 "The magic number again: 0x%(magic2)x\n" \
693 "Checksum: %(checksum)d\n" \
694 "Number of partitions: %(npartitions)d\n" \
695 "Size of boot aread at sn0: %(bbsize)d\n" \
696 "Max size of fs superblock: %(sbsize)d\n" % self.field + \
701 """Main entry point"""
702 usage = "Usage: %prog [options] <input_media>"
703 parser = optparse.OptionParser(usage=usage)
705 parser.add_option("-l", "--list", action="store_true", dest="list",
707 help="list the disklabel on the specified media")
708 parser.add_option("--get-last-partition", action="store_true",
709 dest="last_part", default=False,
710 help="print the label of the last partition")
712 "--get-duid", action="store_true", dest="duid", default=False,
713 help="print the Disklabel Unique Identifier (OpenBSD only)")
714 parser.add_option("-d", "--enlarge-disk", type="int", dest="disk_size",
715 default=None, metavar="SIZE",
716 help="Enlarge the disk to this SIZE (in sectors)")
718 "-p", "--enlarge-partition", action="store_true",
719 dest="enlarge_partition", default=False,
720 help="Enlarge the last partition to cover up the free space")
722 options, args = parser.parse_args(sys.argv[1:])
725 parser.error("Wrong number of arguments")
734 print "%s" % "".join(x.encode('hex') for x in disk.get_duid())
737 if options.last_part:
738 print "%c" % chr(ord('a') + disk.get_last_partition_id())
740 if options.disk_size is not None:
741 disk.enlarge(options.disk_size)
743 if options.enlarge_partition:
744 disk.enlarge_last_partition()
750 if __name__ == '__main__':
753 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :